JP5571509B2 - Electronically controlled valve drive device for internal combustion engine - Google Patents

Description

  The present invention relates to an electronically controlled valve driving apparatus for an internal combustion engine.

  2. Description of the Related Art Conventionally, as an electronically controlled valve drive device for an internal combustion engine, for example, a diesel engine, there is an electronically controlled exhaust valve drive device configured as shown in FIG. When the exhaust valve 202 is opened, the electronically controlled exhaust valve driving device 201 switches the direction control valve 204 to the valve-opening side by an electromagnetic solenoid valve 203 driven by an electronic control device (not shown). High pressure hydraulic pressure is supplied from a hydraulic pressure source 207 including 205, an accumulator 206, and the like to the hydraulic actuator 211 that controls the maximum lift of the exhaust valve 202 through the high pressure pipe 208, the direction control valve 204, and the high pressure pipe 209.

  The hydraulic actuator 211 moves upward in the drawing to the full stroke position, and the hydraulic pressure in the hydraulic actuator 211 is guided to the hydraulic cylinder 213 attached to the exhaust valve 202 through the high pressure pipe 212. The hydraulic cylinder 213 is equipped with a hydraulic piston 214 with a damper 215 in order to avoid overshoot and shocking seating of the exhaust valve 202.

  The high-pressure oil pressure guided from the above-described hydraulic actuator 211 moves the hydraulic piston 214 downward in the drawing against the spring force of the air spring 216 to lift the exhaust valve 202 to the maximum. When the exhaust valve 202 approaches the maximum lift, the valve speed is reduced by the damper 215, and the exhaust valve 202 is fully opened without being overshot.

  When the exhaust valve 202 is closed, when the direction control valve 204 is switched to the valve closing side, the hydraulic piston 214 moves upward in the figure by the spring force of the air spring 216, and the hydraulic pressure in the hydraulic cylinder 213 passes through the high pressure pipe 212. Guided to the hydraulic actuator 211. The hydraulic pressure guided to the hydraulic actuator 211 is discharged to the tank 217 through the high pressure pipe 209, the direction control valve 204, and the low pressure pipe 210. When the exhaust valve 202 is seated, the valve speed is reduced by the action of the above-described damper 215 and smooth seating is performed.

  Further, as a valve driving device for an internal combustion engine, for example, there is one disclosed in Japanese Patent Laid-Open No. 2-248607 (for example, see Patent Document 1). This valve drive device includes an urging means for urging the intake / exhaust valve of the internal combustion engine in the valve opening direction, and a hydraulic means for opening the intake / exhaust valve against the urging force of the urging means by operating hydraulic pressure. , A valve drive device for an internal combustion engine that supplies and discharges hydraulic oil to and from the hydraulic means to open and close the intake and exhaust valves, and discharges hydraulic oil from a supply system or hydraulic means that supplies hydraulic oil to the hydraulic means An opening / closing valve such as a logic valve disposed in at least one of the discharge systems and an electromagnetic switching valve for switching an opening / closing time of the opening / closing valve are provided.

  However, the above-described conventional electronically controlled exhaust valve driving device 201 requires a number of parts such as a hydraulic actuator 211, a high-pressure pipe 212, and a damper 215 provided inside the exhaust valve driving device. There is a problem of high costs. Further, the hydraulic actuator 211 incorporated between the directional control valve 204 and the hydraulic cylinder 213 and the hydraulic piston 214 with the damper 215 incorporated in the exhaust valve 202 are extremely large, and the entire mechanism is large and space is secured. Workability in inspection etc. is poor.

  Further, since a special alloy is used for the damper 215 from the viewpoint of heat resistance, there is a problem that machining is difficult and expensive. The same problem can be considered for the valve drive device described in Patent Document 1.

  Therefore, as shown in FIG. 18, the inventor of the present application, as shown in FIG. 18, attaches to a valve 221 accommodated in a valve drive device of an internal combustion engine and opens the valve 221. A hydraulic pressure generating means 233 for supplying hydraulic pressure to the hydraulic piston 222; a directional control valve 231 for supplying or discharging the hydraulic pressure from the hydraulic pressure generating means 233 to the hydraulic piston 222; a directional control valve 231 and a hydraulic piston 222; Proposed an electronically controlled valve drive for an internal combustion engine comprising a damping actuator 225 connected between the two.

  In this electronically controlled valve drive device for an internal combustion engine, in particular, a hydraulic actuator is provided with an actuator function for driving the hydraulic piston 222 by the hydraulic pressure supplied from the direction control valve 231, and damping for suppressing the driving speed of the hydraulic piston 222. The damping actuator 225 has both functions.

  The damping actuator 225 is connected to a port communicating with the direction control valve 231, and a first check valve 240 that allows the hydraulic pressure to move from the direction control valve 231 to the actuator piston 227 of the damping actuator 225, A first bypass oil passage 242 which is connected in parallel with the first check valve 240 and is composed of a plurality of oil passages which are closed in accordance with the movement of the actuator piston 227 to suppress the speed at the end of the operation of the actuator piston 227; It has.

  Further, the damping actuator 225 is connected to a port communicating with the hydraulic piston 222 attached to the valve 221 to allow a second hydraulic pressure to move from the hydraulic piston 222 to the actuator piston 227 of the damping actuator 225. A check valve 241 and a second oil passage that is connected in parallel with the second check valve 241 and is closed according to the movement of the actuator piston 227 to suppress the speed at the end of the operation of the actuator piston 227. 2 bypass oil passages 243.

JP-A-2-248607 (page 4-7, FIG. 1)

  The electronic control type valve drive device for an internal combustion engine proposed by the present inventor in the above Japanese Patent Application No. 2009-055202 includes a hydraulic actuator, an actuator function for driving the hydraulic piston 222, and a damping function for suppressing the driving speed of the hydraulic piston 222. By using the damping actuator 225 that has both, the number of parts has been greatly reduced, such as eliminating the damper provided inside the exhaust valve drive device, and the manufacturing cost has been greatly reduced. In addition, the entire mechanism can be reduced in size, space is secured, workability in inspection, etc. is extremely good, and the occurrence of cavitation and erosion in the high-pressure piping system can be suppressed. .

  However, as described above, the damping actuator 225 has a damping function because it is configured by the two check valves 240 and 241 and the two bypass oil passages 242 and 243 including a plurality of oil passages. There is a possibility that the structure of the actuator is complicated and large, and the manufacturing cost is high.

  The present invention has been made to solve such problems. When the valve is opened, the maximum lift position is smoothly brought close to prevent overshoot, and when the valve is closed, the seat is smoothly seated to prevent jumping. It is another object of the present invention to provide an electronically controlled valve drive device for an internal combustion engine that can be reduced in size, can be reduced in size, and can greatly reduce manufacturing costs.

  In order to solve the above-described problems, the means employed by the present invention includes a hydraulic piston that is attached to a valve housed in a valve drive device of an internal combustion engine and opens the valve, and a hydraulic pressure that supplies hydraulic pressure to the hydraulic piston. Generating means, a directional control valve for supplying the hydraulic pressure from the hydraulic pressure generating means to the hydraulic piston or discharging the hydraulic pressure of the hydraulic piston, and being connected between the directional control valve and the hydraulic piston and supplied or discharged by the directional control valve. The hydraulic actuator that drives the hydraulic piston by the hydraulic pressure and the flow rate of the hydraulic pressure that is provided inside the hydraulic actuator and that is supplied to the hydraulic piston when the valve is lifted, and that is discharged from the hydraulic piston when the valve is seated And a flow rate control piston that controls and suppresses the drive speed of the hydraulic piston.

  In the electronically controlled valve driving apparatus for an internal combustion engine of the present invention, the flow rate of the hydraulic pressure supplied to the hydraulic piston is controlled when the valve is lifted by the flow control piston provided in the hydraulic actuator, and the hydraulic piston is controlled when the valve is seated. By controlling the flow rate of the hydraulic pressure to be discharged and suppressing the driving speed of the hydraulic piston, it is possible to smoothly approach the maximum lift position when the valve is opened and to be seated smoothly when the valve is closed. Thereby, the overshoot of the valve at the time of valve opening and the jumping of the valve at the time of valve closing can be reliably prevented.

  In particular, by providing a flow control piston inside the hydraulic actuator, the flow control mechanism is simpler in structure than, for example, a structure including two check valves and two bypass oil passages composed of a plurality of oil passages. Therefore, the manufacturing cost can be greatly reduced.

  In the electronically controlled valve drive apparatus for an internal combustion engine, the flow control piston is provided on a valve lift control piston provided on an end surface of the hydraulic actuator piston on the hydraulic piston side, and on an end surface of the hydraulic actuator piston on the direction control valve side. And a valve seating control piston.

  As described above, the flow control piston is configured by the valve lift control piston and the valve seating control piston provided on the end face of the piston of the hydraulic actuator, so that the structure can be simplified and the manufacturing cost can be greatly reduced. Can be achieved.

  In the electronically controlled valve drive system for an internal combustion engine, the valve lift control piston can be fitted in a fluid-tight manner in an oil passage communicating with the hydraulic piston, and the tip is smoothly reduced in diameter to serve as a flow control unit. It is desirable that the valve seating control piston can be fluid-tightly fitted into an oil passage communicating with the direction control valve, and the tip portion is smoothly reduced in diameter to serve as a flow rate control unit.

  As described above, the flow rate control unit that reduces the diameter of the valve lift control piston and the valve seating control piston with a smooth taper includes the valve lift control piston and the valve seating control piston, and an oil passage that is liquid-tightly fitted to these pistons. Can be gradually and smoothly changed. As a result, the valve lift control piston reliably decelerates the valve speed to prevent overshoot when the valve approaches the maximum lift, and the valve seating control piston decelerates the valve speed when the valve is seated and makes it sit smoothly. Thus, jumping can be reliably prevented.

  In the electronically controlled valve drive device for an internal combustion engine, the valve lift control piston and the valve seating control piston control the flow rate of the clearance area between the oil passages fitted to these pistons according to the axial position of the piston of the hydraulic actuator. It is desirable to control the hydraulic flow rate by the unit.

  In this way, the hydraulic pressure supplied to the hydraulic piston that drives the valve by controlling the clearance area between the valve lift control piston and the oil passage in which the valve seating control piston fits in accordance with the axial position of the piston of the hydraulic actuator. And the hydraulic flow rate discharged from the hydraulic piston can be controlled to reduce the valve speed, and the valve speed can be smoothly reduced when the valve approaches the maximum lift or when the valve is seated.

  In the electronically controlled valve drive device for an internal combustion engine, the valve lift control piston and the valve seating control piston are accommodated in a piston accommodation hole provided in an end face of the piston of the hydraulic actuator so as to be able to enter and exit, and the piston accommodation holes It is desirable that the spring protrudes from the end surface of the piston by a spring contracted between the bottom end portion and the base end portion of the piston.

  In this way, the valve lift control piston and the valve seating control piston are accommodated in a piston accommodation hole provided in the end face of the piston of the hydraulic actuator, and protruded from the end face of the piston by the spring, thereby allowing the valve lift control piston or When hydraulic pressure is applied to the tip of the valve seating control piston fitted in the oil passage, the valve lift control piston or valve seating control piston fitted in the oil passage will resist the spring force. Gradually enter the piston housing hole. As a result, the clearance area between the valve lift control piston or the valve seating control piston and the oil passage is gradually widened, and the hydraulic pressure applied to the end face of the piston of the hydraulic actuator is gradually increased.

  In the electronically controlled valve drive system for an internal combustion engine, the valve lift control piston is provided with a piston oil passage having one end opened at the tip of the flow rate controller and the other end opened in the piston accommodation hole of the piston of the hydraulic actuator. One end of the piston of the hydraulic actuator opens to the end face of the piston on the valve lift control piston side, and the other end opens to the piston housing hole, and the valve lift control piston according to the axial position of the valve lift control piston It is desirable that a piston oil passage that can communicate with the piston oil passage is provided.

  Further, in the electronically controlled valve driving apparatus for an internal combustion engine, the valve seat control piston has a piston oil passage having one end opened at a tip end portion of the flow rate control unit and the other end opened at a piston accommodation hole of a piston of a hydraulic actuator. The piston of the hydraulic actuator has one end opened to the end face of the piston on the valve seating control piston side and the other end opened to the piston receiving hole, and the valve seating is controlled according to the axial position of the valve seating control piston. It is desirable that a piston oil passage that can communicate with the piston oil passage of the control piston is provided.

  In this way, the valve lift control piston or the valve seating control piston is provided with a piston oil passage having one end opened at the tip of the flow rate control unit and the other end opened at the piston accommodation hole of the piston of the hydraulic actuator. One end of the actuator piston opens to the end face of each control piston and the other end opens to the piston receiving hole, and communicates with the piston oil passage of the valve seating control piston according to the axial position of each control piston. By providing a piston oil passage that can be used, the valve lift control piston or the valve seating control piston can resist the spring force that is contracted between the bottom end portion of the piston receiving hole and the base end portion of the piston. Gradually entering the housing hole, the piston oil passage of the valve lift control piston or valve seating control piston and the piston of the hydraulic actuator The hydraulic pressure applied to the valve lift control piston or the valve seating control piston is now applied to each end face of the piston of the hydraulic actuator through these piston oil paths. The piston of the actuator can be moved rapidly.

  In the electronically controlled valve drive system for an internal combustion engine, the flow rate control part of the valve lift control piston and the flow rate control part of the valve seating control piston have a concave taper shape that is recessed inward, and the diameter decreases from the base end part to the front end part. It is desirable to be formed as described above.

  In this way, the flow rate control part of the valve lift control piston and the flow rate control part of the valve seating control piston are formed so as to be reduced in diameter from the base end part to the front end part with a concave taper shape recessed inward. The valve speed can be reduced by controlling the flow rate of the hydraulic pressure supplied to the hydraulic piston and the flow rate of the hydraulic pressure discharged from the hydraulic piston, and the valve speed can be adjusted when the valve approaches the maximum lift or when the valve is seated. Decelerate more smoothly.

  As described above, the electronically controlled valve drive device for an internal combustion engine of the present invention is attached to a valve housed in the valve drive device of the internal combustion engine and opens the valve, and supplies hydraulic pressure to the hydraulic piston. A hydraulic pressure generating means, a directional control valve for supplying hydraulic pressure from the hydraulic pressure generating means to the hydraulic piston or discharging a hydraulic pressure of the hydraulic piston, and a directional control valve connected between the directional control valve and the hydraulic piston. The hydraulic actuator that drives the hydraulic piston by the hydraulic pressure that is discharged, and the flow rate of the hydraulic pressure that is provided inside the hydraulic actuator and that is supplied to the hydraulic piston when the valve is lifted, and that is discharged from the hydraulic piston when the valve is seated A flow control piston that controls the flow rate and suppresses the drive speed of the hydraulic piston.

  Therefore, it is possible to smoothly approach the maximum lift position when the valve is opened and to be seated smoothly when the valve is closed, thereby reliably preventing overshoot of the valve when the valve is opened and jumping of the valve when the valve is closed. In particular, the hydraulic actuator can be easily and miniaturized, and the manufacturing cost can be greatly reduced.

1 is an external view of an electronically controlled exhaust valve driving device for an internal combustion engine to which an electronically controlled valve driving device for an internal combustion engine according to an embodiment of the present invention is applied. FIG. 2 is a conceptual diagram of the electronically controlled exhaust valve driving device shown in FIG. 1. It is sectional drawing of the valve apparatus and hydraulic actuator of the electronic control type exhaust valve drive device shown in FIG. FIG. 4 is an enlarged view of the hydraulic actuator shown in FIG. 3. It is sectional drawing which shows the state which the valve lift control piston shown in FIG. 3 protruded from the piston. It is sectional drawing which shows the state which the valve seating control piston shown in FIG. 3 protruded from the piston. It is sectional drawing seen from the arrow AA of the valve lift control piston shown to Fig.5 (a). It is sectional drawing seen from the arrow BB of the valve lift control piston shown in FIG.5 (b). It is sectional drawing which shows the state by which the valve lift control piston shown in FIG. 3 was pushed into the piston. It is sectional drawing which shows the state by which the valve seating control piston shown in FIG. 3 was pushed into the piston. FIG. 4 is a cross-sectional view illustrating a state at the end of valve opening of the hydraulic actuator illustrated in FIG. 3. FIG. 4 is a first explanatory view showing the operation of a piston and a valve seating control piston when the hydraulic actuator shown in FIG. 3 is opened. FIG. 4 is a second explanatory view showing the operation of the piston and the valve seating control piston when the hydraulic actuator shown in FIG. 3 is opened. FIG. 6 is a third explanatory view showing the operation of the piston and the valve seating control piston when the hydraulic actuator shown in FIG. 3 is opened. FIG. 4 is a first explanatory view showing the operation of a piston and a valve lift control piston when the hydraulic actuator shown in FIG. 3 is opened. FIG. 4 is a second explanatory view showing the operation of the piston and the valve lift control piston when the hydraulic actuator shown in FIG. 3 is opened. FIG. 4 is a third explanatory view showing the operation of the piston and the valve lift control piston when the hydraulic actuator shown in FIG. 3 is opened. It is a figure which shows an example of the area change of the valve lift side oil path by the valve lift control piston shown to Fig.9 (a)-FIG.9 (c). It is a figure which shows an example of the area change of the valve seat side oil path by the valve seat control piston shown to Fig.8 (a)-FIG.8 (c). It is a figure which shows an example of the operating characteristic of the valve controlled by the hydraulic actuator and flow control piston which were shown in FIG. It is a figure which shows another embodiment of the valve lift control piston and valve seating control piston which concern on this invention. It is a figure which shows another operation state of the valve lift control piston and valve seating control piston which are shown in FIG. It is a figure which shows another embodiment of the flow volume control part of the valve lift control piston and valve seating control piston which concern on this invention. It is a figure which shows another embodiment of the flow volume control part of the valve lift control piston and valve seating control piston which concern on this invention. It is a schematic explanatory drawing of the electronically controlled exhaust valve drive device of the conventional diesel engine. FIG. 18 is a schematic explanatory diagram of an electronically controlled exhaust valve driving device for a diesel engine different from FIG. 17.

  An embodiment for carrying out the invention of an electronically controlled valve driving device for an internal combustion engine according to the present invention will be described in detail with reference to FIGS. FIG. 1 is an external view showing an outline of an electronically controlled exhaust valve driving device to which an electronically controlled valve driving device for an internal combustion engine according to the present invention is applied, and FIG. 2 is an electronic control of the internal combustion engine shown in FIG. It is a conceptual diagram of a type exhaust valve drive device.

  As shown in FIGS. 1 and 2, the exhaust valve driving device 20 includes an exhaust valve 21, a hydraulic piston 22 that is attached to the upper end of the valve shaft 21 a of the exhaust valve 21 and opens the exhaust valve 21, and a valve An air spring 24 that is attached in the middle of the shaft 21a and closes the exhaust valve 21 (restoring operation) is accommodated.

  A hydraulic actuator 25 is attached to the upper portion 20 a of the exhaust valve driving device 20. The hydraulic actuator 25 has an actuator function for driving the hydraulic piston 22 and a damping function for suppressing the driving speed of the hydraulic piston 22, and is connected to the hydraulic cylinder 23 of the hydraulic piston 22 via the oil passage 61. ing.

  A hydraulic block 30 separate from the exhaust valve driving device 20 is disposed on the side of the exhaust valve driving device 20, and a directional control valve 31 and an accumulator 35 are attached to the hydraulic block 30. Further, an electromagnetic solenoid 32 for switching and controlling the direction control valve 31 is attached to the direction control valve 31.

  Oil passages 30a, 30b, and 30c are provided in the hydraulic block 30 and are connected to corresponding ports (not shown) of the direction control valve 31. The hydraulic source 33 includes a hydraulic pump 34, an accumulator 35, and the like. The hydraulic pump 34 is connected to the oil passage 30 a via a high pressure pipe 62, and the accumulator 35 is connected to the high pressure pipe 62.

  The oil passage 30 a guides high pressure oil pressure from the oil pressure source 33 to the direction control valve 31. The oil passage 30 b is connected to the hydraulic actuator 25 via the high-pressure pipe 63. The oil passage 30 c discharges hydraulic pressure from the direction control valve 31 to the tank 37 through the low pressure pipe 64.

  Next, the hydraulic actuator 25 and the flow control piston 41 provided therein will be described. 3 is a cross-sectional view of the upper portion 20a of the exhaust valve driving device 20 and the hydraulic actuator 25 shown in FIG. 1, and FIG. 4 is an enlarged view of the hydraulic actuator 25 shown in FIG.

  As shown in FIG. 3, the hydraulic actuator 25 has a piston 27 slidably accommodated in a cylinder 26 thereof. A port (oil passage) 26a communicating with the oil passage 61 of the hydraulic piston 22 of the exhaust valve device 20 is provided on the end face of the cylinder 26 on the hydraulic piston 22 side, and the end face on the direction control valve 31 (see FIG. 2) side is provided. Is provided with a port (oil passage) 26 b communicating with the direction control valve 31.

  As shown in FIG. 4, the piston 27 is provided with a piston accommodation hole 27 a for accommodating a valve lift control piston (flow rate control piston) 42 at the center position of the end face on the hydraulic piston 22 side, and the direction control valve 31 side. A piston accommodation hole 27b for accommodating a valve seating control piston (flow rate control piston) 43 is provided at the center position of the end face of the cylinder.

  The piston 27 has one end opened on the end surface of the piston 27 on the hydraulic piston 22 (see FIG. 2) side and the other end opened in the piston accommodating hole 27a, for example, two piston oil passages 27c, One or more, for example, two piston oil passages 27d each having one end opened on the end face of the piston 27 on the direction control valve 31 (see FIG. 2) side and the other end opened in the piston accommodation hole 27b are provided. .

  The piston 27 has a cylindrical shape with a bottom, and a large-diameter piston 28 in which a hydraulic pressure supply hole 28a having a diameter larger than the end surface opening position of the piston accommodation hole 27b is provided in the bottom portion. It is slidably fitted to the side to form a double piston. The large diameter piston 28 can move within the cylinder 26 integrally with the piston 27 by a predetermined stroke shorter than the stroke of the piston 27. The hydraulic pressure supply hole 28 a of the large diameter piston 28 is for supplying hydraulic pressure to the piston 27.

  The hydraulic actuator 25 requires a large force because the gas pressure in the cylinder is high when the exhaust valve 21 (see FIG. 2) is initially opened. For this reason, the large-diameter piston 28 is driven by a high-pressure hydraulic pressure introduced into the port 26b. Is used to generate a large hydraulic pressure F1 and supply the hydraulic pressure F1 from the port 26a to the hydraulic cylinder 23 (see FIG. 2). The large-diameter piston 28 moves from the position shown in FIG. 4 by a predetermined stroke and stops at the position shown in FIG. Until this stop position, the piston 27 moves integrally with the large-diameter piston 28.

  After the exhaust valve 21 starts to open, the piston 27 generates a hydraulic pressure F2 smaller than the hydraulic pressure F1 and supplies the hydraulic pressure F2 to the hydraulic cylinder 23 from the port 26a. At this time, the large-diameter piston 28 is stopped at the position shown in FIG. Accordingly, unnecessary piston operation can be eliminated, loss of hydraulic pressure during the opening operation of the exhaust valve 21 can be suppressed, and fuel consumption can be improved.

  The valve lift control piston 42 can be liquid-tightly fitted to the port 26a of the cylinder 26, the base end portion has a large diameter, the tip end portion is reduced in diameter with a smooth taper, and the flow rate control portion 42a Is done. The flow rate control unit 42a has a concave taper shape in which, for example, the large-diameter base end portion is slightly recessed inward, and the diameter is reduced from the base end portion to the tip end portion.

  The valve seating control piston 43 can be fitted into the port 26b of the cylinder 26 in a liquid-tight manner, and the base end portion has a large diameter and the tip end portion is reduced in diameter with a smooth taper, thereby controlling the flow rate. Part 43a. The flow rate control unit 43a has a concave taper shape in which the large-diameter base end side is slightly recessed inward, similar to the flow rate control unit 42a of the valve lift control piston 42, for example, and the diameter is reduced from the base end portion to the tip end portion. ing.

  As shown in FIGS. 5A and 5B, the valve lift control piston 42 and the valve seating control piston 43 can be slidably accommodated in the piston accommodation holes 27a and 27b, and come out by the end plates 44 and 45. Is prevented. Then, springs 46 and 47 are respectively contracted between the base end portions of the valve lift control piston 42 and the valve seating control piston 43 and the bottom end portions of the piston accommodation holes 27a and 27b. Thereby, the valve lift control piston 42 and the valve seating control piston 43 can project from the end face of the piston 27 by the urging force of the springs 46 and 47, respectively.

  As shown in FIG. 5C, the cylindrical base end portion that slides with the piston accommodation hole 27a of the valve lift control piston 42 is chamfered at intervals of 120 ° at three locations on the circumference of the spring 46 side. Thus, three oil passages 42d extending in the axial direction are formed on the spring 46 side.

  As shown in FIG. 5D, the cylindrical base end portion that slides with the piston accommodation hole 27b of the valve seating control piston 43 is chamfered at intervals of 120 ° at three locations on the circumference on the spring 47 side. Thus, three oil passages 43d extending in the axial direction are formed on the spring 47 side.

  The flow rate control units 42a and 43a of the valve lift control piston 42 and the valve seating control piston 43 that are reduced in diameter with a smooth taper are oils that are fitted into the valve lift control piston 42 and the valve seating control piston 43 in a liquid-tight manner, respectively. By adjusting the gap area with the path, that is, the gap area between the ports 26a and 26b (see FIG. 4) of the cylinder 26 of the hydraulic actuator 25, in accordance with the axial position of the piston 27, as described later, A damping function is provided when the exhaust valve 21 is lifted and seated.

  Further, one end of each of the valve lift control piston 42 and the valve seating control piston 43 is opened at the tip of each flow rate control unit 42a, 43a. For example, piston oil passages 42 b and 43 b are provided that branch into two and have the other ends opened to the piston accommodation holes 27 a and 27 b of the piston 27 of the hydraulic actuator 25.

  The openings 42c and 43c at the other ends of the piston oil passages 42b and 43b are formed in an annular shape on the cylindrical outer peripheral portions of the valve lift control piston 42 and the valve seating control piston 43. On the other hand, in the piston oil passages 27c and 27d of the piston 27 described above, openings 27e and 27f that open to the piston accommodation holes 27a and 27b are respectively formed annularly on the inner peripheral portions of the piston accommodation holes 27a and 27b. ing.

  The opening portions 42c and 43c of the piston oil passages 42b and 43b of the valve lift control piston 42 and the valve seating control piston 43 and the opening portions 27e and 27f of the piston oil passages 27c and 27d of the piston 27 are shown in FIG. As shown in (b), in a state where the valve lift control piston 42 and the valve seating control piston 43 are most protruded from the piston 27, the axial position is shifted and the communication is not established.

  However, the openings 42c and 43c of the piston oil passages 42b and 43b of the valve lift control piston 42 and the valve seating control piston 43 and the openings 27e and 27f of the piston oil passages 27c and 27d of the piston 27 are shown in FIG. ), (B), the valve lift control piston 42 and the valve seating control piston 43 are in full communication with each other at least when they are pushed most into the piston receiving holes 27a and 27b of the piston 27. Yes.

  That is, the piston oil passages 42b and 43b of the valve lift control piston 42 and the valve seating control piston 43 and the piston oil passages 27c and 27d of the piston 27 correspond to the axial positions of the valve lift control piston 42 and the valve seating control piston 43. Communicate with each other. From the openings 42c and 43c of the piston oil passages 42b and 43b of the valve lift control piston 42 and the valve seating control piston 43, hydraulic pressure for pushing the piston 27 is supplied mainly at the initial stage of movement of the piston 27.

  On the other hand, three oil passages 42d provided at three locations on the circumference of the above-described valve lift control piston 42 and the opening 27e of the piston oil passage 27c of the piston 27 are shown in FIGS. As shown in (a), the valve lift control piston 42 is always in communication regardless of the position in the axial direction. Also, three oil passages 43d provided at three locations on the circumference of the valve seating control piston 43 and the opening 27f of the piston oil passage 27d of the piston 27 are shown in FIGS. 5 (b) and 6 (b). As shown, the valve seating control piston 43 is always in communication regardless of the axial position.

  With such a configuration, as will be described later, the valve lift control piston 42 decelerates the valve speed when the exhaust valve 21 approaches the maximum lift to reliably prevent overshoot, and the valve seating control piston 43 When 21 is seated, the valve speed is reduced and seated smoothly to reliably prevent jumping.

  Next, the operation of the exhaust valve driving device 20 will be described with reference to FIGS. As shown by the solid line in FIG. 2, when the exhaust valve 21 is closed, the piston 27 of the hydraulic actuator 25 is in the closed position (end position) on the port 26b side, as shown in FIGS. It has stopped. And the flow control part 43a of the valve seating control piston 43 is liquid-tightly fitted in the port 26b of the cylinder 26 of the hydraulic actuator 25 as shown in FIG.

  When the solenoid valve 32 is driven by an electronic control device (not shown) to open the exhaust valve 21, the solenoid valve 32 drives the direction control valve 31 in the valve opening direction, and the high hydraulic pressure of the hydraulic source 33 is changed to the hydraulic pressure. The high pressure pipe 63 is supplied through the block 30.

  The high pressure hydraulic pressure supplied from the direction control valve 31 through the high pressure pipe 63 is supplied to the port 26b of the cylinder 26 of the hydraulic actuator 25, and as shown by the arrows in FIGS. 5 (b) and 8 (a). Pressure is applied to the piston oil passage 43b of the seating control piston 43. As a result, the valve seating control piston 43 is pushed into the piston accommodating hole 27b against the spring force of the spring 47 and abuts against the bottom thereof, as shown in FIGS.

  For this reason, the opening 43c of the piston oil passage 43b of the valve seating control piston 43 and the opening 27f of the piston oil passage 27d of the piston 27 communicate with each other, and the hydraulic pressure of the piston oil passage 43b passes through the piston oil passage 27d. It comes to the end surface of the large-diameter piston 28 shown in FIG. As a result, the piston 27 and the large-diameter piston 28 start to move in the left direction in the figure, and at the same time, the flow control unit 43a of the valve seating control piston 43 comes out of the port 26b of the cylinder 26 as shown in FIG. .

  Since the flow rate control unit 43a is tapered, the hydraulic pressure flows into the cylinder 26 through an annular clearance area (opening area) between the port 26b and the hydraulic pressure flows into the piston 27 and the large-diameter piston 28. It comes to cover the whole end face of. As a result, the piston 27 and the large-diameter piston 28 move rapidly together in the left direction in the figure.

  When the valve seating control piston 43 is completely removed from the port 26b, a large amount of hydraulic pressure flows into the cylinder 26 from the port 26b, and the piston 27 and the large-diameter piston 28 are integrated into the left side in the figure with a large hydraulic pressure. Move rapidly. As shown in FIG. 7, the stroke of the large-diameter piston 28 is shorter than the stroke of the piston 27. Accordingly, the piston 27 generates a large hydraulic pressure at the initial stage of movement.

  At the same time, as shown in FIG. 5 (b), a large hydraulic pressure is applied to the piston seating hole 27 b on the spring 47 side through the piston oil passage 27 d and the oil passage 43 d of the valve seating control piston 43. A back pressure is applied to cooperate with the spring 47 to push the valve seating control piston 43 outward. As a result, the valve seating control piston 43 returns to the original state.

  As the piston 27 of the hydraulic actuator 25 moves, the hydraulic pressure in the cylinder 26 pushes down the hydraulic piston 22 through the port 26a and the oil passage 61 shown in FIGS. 2 and 3 and opens the exhaust valve 21. Then, as shown in FIG. 9A, after the piston 27 moves to the position near the end, as shown in FIG. 9B, the flow rate control part 42a of the valve lift control piston 42 enters the port 26a.

  Since the flow rate control unit 42a is tapered, the annular gap area (opening area) with the port 26a is gradually reduced, and the flow rate of the hydraulic pressure for driving the hydraulic piston 22 shown in FIG. Decrease gradually. Accordingly, the opening speed of the exhaust valve 21 shown in FIG. 2 is reduced.

  Then, as shown in FIGS. 7 and 9C, when the piston 27 moves to the end position and the valve lift control piston 42 is fluid-tightly fitted with the port 26a, the exhaust valve 21 shown in FIG. It stops at the maximum lift position (maximum valve opening position) indicated by the two-dot chain line in the figure.

  An example of the area change of the oil passage (port 26a) on the valve lift side by the valve lift control piston 42 is shown in FIG. The valve lift control piston 42 described above reduces the valve speed when the exhaust valve 21 approaches the maximum lift position, and reliably prevents overshoot of the exhaust valve 21.

  As shown in FIG. 2, when the electromagnetic solenoid 32 is driven by an electronic control device (not shown) to close the exhaust valve 21, the direction control valve 31 is driven in the valve closing direction, and the hydraulic pressure in the high pressure pipe 63 is changed to the direction. It is discharged to the tank 37 through the control valve 31 and the low pressure pipe 64. Accordingly, the hydraulic pressure in the actuator cylinder 26 of the hydraulic actuator 25 is discharged to the high-pressure pipe 63, and the hydraulic pressure in the actuator cylinder 26 is reduced.

  As the hydraulic pressure of the actuator cylinder 26 decreases, the hydraulic piston 22 moves upward by the spring force of the air spring 24, and the hydraulic pressure in the hydraulic cylinder 23 is introduced into the cylinder 26. Along with this, pressure is applied to the piston oil passage 42b of the valve lift control piston 42 as shown by the arrow in FIG. As a result, the valve lift control piston 42 is pushed into the piston accommodation hole 27a against the spring force of the spring 46, as shown in FIG.

  When the valve lift control piston 42 is pushed into the piston accommodation hole 27a, the opening 42c of the piston oil passage 42b of the valve lift control piston 42 and the opening 27e of the piston oil passage 27c of the piston 27 communicate with each other, and the valve lift The oil pressure applied to the piston oil passage 42b of the control piston 42 is applied to the end surface of the piston 27 through the piston oil passage 27c. As a result, the piston 27 starts to move to the right in the figure, and the flow rate control unit 42a of the valve lift control piston 42 begins to come out of the port 26a of the cylinder 26.

  Since the flow rate control unit 42a is tapered, the hydraulic pressure flows into the cylinder 26 through an annular clearance area (opening area) between the port 26a and the hydraulic pressure is applied to the entire end face of the piston 27. It becomes like this. Thereby, the piston 27 moves rapidly in the right direction in the figure.

  As the piston 27 moves to the right, the flow rate control unit 42a of the valve lift control piston 42 is completely removed from the port 26a, and the clearance area (opening area) between the port 27a and the port 27a is further increased. As a result, the flow rate of the hydraulic pressure flowing from the hydraulic cylinder 23 into the cylinder 26 further increases, and the piston 27 moves more rapidly in the right direction in the figure.

  At the same time, as shown in FIG. 5 (a), a large hydraulic pressure is applied to the piston accommodation hole 27 a on the spring 46 side through the piston oil passage 27 c and the oil passage 42 d of the valve lift control piston 42 to the valve lift control piston 42. A back pressure is applied to cooperate with the spring 46 to push the valve lift control piston 42 outward. As a result, the valve lift control piston 42 returns to the original state.

  When the exhaust valve 21 approaches the seating position (valve closing position), as shown in FIG. 4, the flow rate control unit 43a of the valve seating control piston 43 enters the port 26b, and the clearance area (opening area) between the port 26b and the port 26b. Gradually decreases. Thereby, the moving speed of the piston 27 is decelerated, and the flow rate of the hydraulic pressure flowing into the cylinder 26 from the hydraulic cylinder 23 gradually decreases.

  Accordingly, the opening speed of the exhaust valve 21 shown in FIG. 2 is reduced. When the piston 27 moves to the end position and the valve seating control piston 43 is fluid-tightly fitted to the port 26b, the exhaust valve 21 is seated as shown by a two-dot chain line in FIG. FIG. 11 shows an example of a change in the area of the oil passage (port 26 b) on the valve seating side by the valve seating control piston 43.

  When the exhaust valve 21 approaches the seating position (valve closing position), the valve seating control piston 43 reliably prevents jumping of the exhaust valve 21 by reducing the valve speed, and the exhaust valve 21 is applied to the valve seat by inertia force. Prevent collisions. Thereby, as shown by a solid line in FIG. 2, the smooth seating of the exhaust valve 21 is performed. Thus, the valve opening operation and the valve closing operation of the exhaust valve 21 are performed.

  As described above, when the exhaust valve 21 approaches the maximum lift position (valve opening position), the valve speed is reduced by the valve lift control piston 42. Further, when the exhaust valve 21 approaches the seating position (valve closing position), the valve operating speed is reduced by the valve seating control piston 43, whereby the valve operating characteristics as shown in FIG. 10 can be obtained. In FIG. 10, a curved portion A indicates when the exhaust valve 21 is lifted, and a curved portion B indicates when the exhaust valve 21 is seated.

  The hydraulic actuator 25 has both a damping function and an actuator function, and has very high responsiveness. Accordingly, the inside of the high-pressure piping system such as the high-pressure pipe 63 is unlikely to become negative pressure, and the occurrence of cavitation erosion in the high-pressure piping system can be suppressed.

  13 and 14 show another embodiment relating to the configuration of the flow rate control piston including the valve lift control piston and the valve seating control piston. Portions similar to those in the above-described valve lift control piston 42 and valve seating control piston 43 will be described with the same reference numerals.

  The hydraulic actuator 125 has a piston 127 slidably accommodated in a cylinder 126 thereof. The piston 127 is provided with a piston accommodation hole 127a for accommodating a valve lift control piston (flow rate control piston) 142 at the center position of the end face on the hydraulic piston 22 side, and at the center position of the end face on the direction control valve 31 side. A piston accommodation hole 127b for accommodating the valve seating control piston (flow rate control piston) 143 is provided.

  The piston 127 has one end opened on the end surface of the piston 127 on the hydraulic piston 22 side and the other end opened on the piston accommodation hole 127a, and one end on the end surface of the piston 127 on the direction control valve 31 side. A piston oil passage 127d having an opening and the other end opening to the piston accommodation hole 127b is provided.

  The piston 127 has a cylindrical shape with a bottom, and a large-diameter piston 128 in which a hydraulic pressure supply hole 128a having a diameter larger than the end surface opening position of the piston accommodation hole 127b is provided in the bottom portion of the piston 127. It is slidably fitted to the side to form a double piston. The large diameter piston 128 and the piston 127 operate in the same manner as the large diameter piston 28 and the piston 27 of the hydraulic actuator 25 described above.

  Further, the flow rate control unit 142a of the valve lift control piston 142 and the flow rate control unit 143a of the valve seating control piston 143 are formed in the same manner as the flow rate control units 42a and 43a of the hydraulic actuator 25 described above. 142a and 143a are formed in a solid shape, and are different in that a piston oil passage is not formed therein. The valve lift control piston 142 and the valve seating control piston 143 are slidably accommodated in the piston accommodation holes 127a and 127b, and are prevented from coming out by the end plates 144 and 145.

  Springs 146 and 147 are respectively contracted between the base ends of the valve lift control piston 142 and the valve seating control piston 143 and the bottom ends of the piston receiving holes 127a and 127b. Thereby, the valve lift control piston 142 and the valve seating control piston 143 can each protrude from the end surface of the piston 27.

  The piston oil passages 127c and 127d of the piston 127 are always in the state in which the springs 146 and 147 are contracted, regardless of the axial positions of the valve lift control piston 142 and the valve seating control piston 143. Each communicates with the accommodation hole 127b.

  Next, the operation of the exhaust valve driving device will be described with reference to FIGS. As shown by the solid line in FIG. 2, when the exhaust valve 21 is closed, the piston 127 of the hydraulic actuator 125 stops at the valve closed position (end position) on the port 126b side as shown in FIG. Yes. The valve seating control piston 143 is liquid-tightly fitted in the port 126b.

  The high pressure oil pressure supplied from the direction control valve 31 through the high pressure pipe 63 to open the exhaust valve 21 is supplied to the port 126b of the cylinder 126 of the hydraulic actuator 125, and the valve seating control piston 143 is connected to the spring 147. It is pushed into the piston accommodation hole 127b against the spring force.

  As the valve seating control piston 143 is pushed, the flow rate control unit 143a comes out of the port 126b of the cylinder 126. Since the flow rate control unit 143a has a tapered shape, an annular gap area (opening area) between the port 126b and the port 126b gradually increases, and the flow rate of hydraulic pressure flowing into the cylinder 126 increases accordingly. Then, the hydraulic pressure is gradually applied to the end surfaces of the piston 127 and the large-diameter piston 128. As a result, the piston 127 and the large-diameter piston 128 begin to move in the left direction in the figure.

  When the valve seating control piston 143 is completely removed from the port 126b, a large amount of hydraulic pressure flows into the cylinder 126 from the port 126b, and the piston 127 and the large-diameter piston 128 are integrated into a large body and rapidly moved to the left in the figure. Move to. When the hydraulic pressure flows into the cylinder 126, a part thereof flows into the piston accommodation hole 127b through the piston oil passage 127d, applies back pressure to the valve seating control piston 143, and cooperates with the spring 147 to apply the valve seating. The control piston 143 is pushed out. As a result, the valve seating control piston 143 returns to the original state.

  When the piston 127 further moves leftward in the figure, the flow rate control unit 142a of the valve lift control piston 142 enters the port 126a as shown in FIG. Since the flow rate control unit 142a is tapered, an annular clearance area (opening area) with the port 126a is gradually reduced, and the flow rate of the hydraulic pressure for driving the hydraulic piston 22 is gradually reduced.

  Accordingly, the valve opening speed of the exhaust valve 21 is reduced. When the piston 127 moves to the end position and the valve lift control piston 142 is fluid-tightly fitted with the port 126a, the exhaust valve 21 is at the maximum lift position (maximum valve opening position) indicated by the two-dot chain line in FIG. To stop.

  As shown in FIGS. 2 and 14, when the electromagnetic solenoid 32 is driven by an electronic control device (not shown) to close the exhaust valve 21, the direction control valve 31 is driven in the valve closing direction, and the high-pressure pipe 63 is closed. The hydraulic pressure is discharged to the tank 37 through the direction control valve 31 and the low pressure pipe 64. As a result, the hydraulic pressure in the actuator cylinder 126 of the hydraulic actuator 125 is discharged to the high pressure pipe 63, and the hydraulic pressure in the actuator cylinder 126 decreases.

  As the hydraulic pressure of the actuator cylinder 126 decreases, the hydraulic piston 22 moves upward by the spring force of the air spring 24, and the hydraulic pressure in the hydraulic cylinder 23 is introduced into the cylinder 126. Accordingly, the valve lift control piston 142 is pushed into the piston accommodation hole 127a against the spring force of the spring 146.

  When the valve lift control piston 142 is pushed into the piston accommodation hole 127a, the hydraulic pressure is gradually applied to the piston 127 through the gap between the valve lift control piston 142 and the port 126a, and the piston 127 starts to move rightward in the drawing. As the piston 127 moves to the right, the flow rate control unit 142a of the valve lift control piston 142 comes out of the port 126a, and the clearance area (opening area) between the port 126a and the port 126a gradually increases. As a result, the flow rate of the hydraulic pressure flowing from the hydraulic cylinder 23 into the cylinder 126 increases, and the piston 127 rapidly moves to the right in the figure.

  When the exhaust valve 21 approaches the seating position (valve closing position), the flow control unit 143a of the valve seating control piston 143 enters the port 126b as shown in FIG. 13, and the clearance area (opening area) between the port 126b and the port 126b is reached. ) Gradually decreases. Thereby, the moving speed of the piston 127 is decelerated, and the flow rate of the hydraulic pressure flowing into the cylinder 126 from the hydraulic cylinder 23 gradually decreases.

  Accordingly, the valve opening speed of the exhaust valve 21 is reduced. When the valve seating control piston 143 is fluid-tightly fitted to the port 126b, the exhaust valve 21 is seated as shown by a two-dot chain line in FIG. When the exhaust valve 21 approaches the seating position (valve closing position), the valve seating control piston 143 reliably prevents the exhaust valve 21 from jumping by reducing the valve speed, and the exhaust valve 21 is applied to the valve seat by inertia force. Prevent collisions. Thereby, as shown by a solid line in FIG. 2, the smooth seating of the exhaust valve 21 is performed. Thus, the valve opening operation and the valve closing operation of the exhaust valve 21 are performed. The rest is the same as in the case of the hydraulic actuator 25 described above, and a description thereof will be omitted.

  15 and 16 show another embodiment relating to the shape of the flow rate control unit of the flow rate control piston including the valve lift control piston and the valve seating control piston.

  The flow rate control portions 42a and 43a of the flow rate control piston 41 described above are formed so that the proximal end side is formed in a concave taper shape that is slightly recessed inward, and the diameter is reduced from the proximal end portion to the distal end portion. The flow rate control portion 148a of the flow rate control piston 148 shown in FIG. 15 has a convex taper shape slightly bulging outward, and is formed so as to decrease in diameter from the proximal end portion to the distal end portion. Further, the flow rate control unit 149a of the flow rate control piston 149 shown in FIG. 16 forms a linear truncated cone-shaped tapered surface from the large-diameter base end so that the diameter decreases from the base end toward the front end. It is formed.

  The flow rate control unit of the flow rate control piston is not limited to the above-described linear taper surface, a curved surface bulging outward, or a curved surface recessed inward, and can be set in various shapes. Moreover, the shape of this flow control part can be optimally set from the graph of the area change of an oil passage as shown, for example in FIG.10 and FIG.11.

  The above-described electronically controlled valve drive device for an internal combustion engine is merely an example, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

  The present invention is not limited to an electronically controlled valve drive device for an internal combustion engine, and can of course be used for various internal combustion engine valve drive devices and hydraulic mechanisms.

20 Exhaust valve drive device 20a Upper part 21 Exhaust valve 21a Valve shaft 22 Hydraulic piston 23 Hydraulic cylinder 24 Air spring 25 Hydraulic actuator 26 Cylinder 26a, 26b Port 27 Piston 27a, 27b Piston accommodating hole 27c, 27d Piston oil passage 27e, 27f Opening 28 Large-diameter piston 28a Hydraulic supply hole 30 Hydraulic block 30a, 30b, 30c Oil passage 31 Direction control valve 32 Solenoid valve 33 Hydraulic source 34 Hydraulic pump 35 Accumulator 37 Tank 41 Flow control piston 42 Valve lift control piston (flow control piston)
42a Flow control unit 42b Piston oil passage 42c Opening 42d Oil passage 43 Valve seating control piston (flow control piston)
43a Flow control unit 43b Piston oil passage 43c Opening 43d Oil passage 44, 45 End plate 46, 47 Spring 61 Oil passage 62, 63 High pressure pipe 64 Low pressure pipe 125 Hydraulic actuator 126 Cylinder 126a, 126b Port 127 Piston 127a, 127b Piston housing Hole 127c, 127d Piston oil passage 128 Large diameter piston 128a Hydraulic supply hole 141 Flow rate control piston 142 Valve lift control piston (flow rate control piston)
142a Flow Control Unit 143 Valve Seat Control Piston (Flow Control Piston)
143a Flow control units 144, 145 End plates 146, 147 Springs 148, 149 Flow control pistons 148a, 149a Flow control unit 201 Electronically controlled exhaust valve drive device 202 Exhaust valve 203 Solenoid valve 204 Directional control valve 205 Hydraulic pump 206 Accumulator 207 Hydraulic pressure Source 208, 209, 212 High pressure pipe 210 Low pressure pipe 211 Hydraulic actuator 213 Hydraulic cylinder 214 Hydraulic piston 215 Damper 216 Air spring 217 Tank 221 Valve 222 Hydraulic piston 225 Damping actuator 227 Actuator piston 231 Directional control valve 233 Hydraulic supply means 240, 241 Check valves 242, 243 Bypass oil passage

Claims (8)

A hydraulic piston (22) attached to a valve (21) housed in a valve drive device (20) of an internal combustion engine to open the valve; a hydraulic pressure generating means (33) for supplying hydraulic pressure to the hydraulic piston; A directional control valve (31) for supplying the hydraulic pressure from the hydraulic pressure generating means to the hydraulic piston or discharging the hydraulic pressure of the hydraulic piston, and the directional control valve connected between the directional control valve and the hydraulic piston. A hydraulic actuator (25) for driving the hydraulic piston by hydraulic pressure supplied or discharged by the valve, and a flow rate of the hydraulic pressure provided in the hydraulic actuator to be supplied to the hydraulic piston when the valve is lifted. The flow rate control pistons (41, 14) which control the flow rate of the hydraulic pressure discharged from the hydraulic piston when seated, and suppress the driving speed of the hydraulic piston. ) And the electronically controlled valve drive for an internal combustion engine wherein the flow control piston, said hydraulic piston-side valve lift control piston provided on the end face of the hydraulic actuator piston (27, 127) (42, 142) and a valve seating control piston (43, 143) provided on the end face on the direction control valve side of the piston of the hydraulic actuator, and the valve lift control piston and the valve seating control piston are the same as those of the hydraulic actuator. The piston is accommodated in a piston accommodation hole (27a, 27b, 127a, 127b) provided in the end face of the piston so as to be able to enter and exit, and is contracted between the bottom end portion of the piston accommodation hole and the base end portion of the piston. spring (46,47,146,147) by inner, characterized in that protrudes from an end face of the piston Electronically controlled valve actuating device of the engine. A hydraulic piston (22) attached to a valve (21) housed in a valve drive device (20) of an internal combustion engine to open the valve; a hydraulic pressure generating means (33) for supplying hydraulic pressure to the hydraulic piston; A directional control valve (31) for supplying the hydraulic pressure from the hydraulic pressure generating means to the hydraulic piston or discharging the hydraulic pressure of the hydraulic piston, and the directional control valve connected between the directional control valve and the hydraulic piston. A hydraulic actuator (25) for driving the hydraulic piston by hydraulic pressure supplied or discharged by the valve, and a flow rate of the hydraulic pressure provided in the hydraulic actuator to be supplied to the hydraulic piston when the valve is lifted. The flow rate control pistons (41, 14) which control the flow rate of the hydraulic pressure discharged from the hydraulic piston when seated, and suppress the driving speed of the hydraulic piston. ) And the electronically controlled valve drive for an internal combustion engine wherein the flow control piston, said hydraulic piston-side valve lift control piston provided on the end face of the hydraulic actuator piston (27, 127) (42, 142) and a valve seating control piston (43, 143) provided on the end face of the piston of the hydraulic actuator on the direction control valve side, and the valve lift control piston communicates with the hydraulic piston ( 26a, 126a) can be fitted in a fluid-tight manner, and the tip end portion is smoothly reduced in diameter to form a flow rate control unit (42a, 142a), and the valve seating control piston communicates with the directional control valve. The passage (26b, 126b) can be fitted in a fluid-tight manner, and the tip portion is smoothly reduced in diameter to form a flow rate control unit (43a, 143a). The flow control unit of the flow rate control unit and the valve seating control piston bet control piston, that it is formed so as to be reduced in diameter toward the distal end portion from the proximal end forms a concave tapered recessed inwardly An electronically controlled valve drive device for an internal combustion engine. The valve lift control pistons (42, 142) can be fluid-tightly fitted into oil passages (26a, 126a) communicating with the hydraulic pistons, and the tip portions thereof are smoothly reduced in diameter so that the flow rate control unit (42a). 142a), and the valve seating control piston (43, 143) can be fluid-tightly fitted in an oil passage (26b, 126b) communicating with the directional control valve, and the tip portion can be smoothly reduced in diameter. The electronically controlled valve drive device for an internal combustion engine according to claim 1 , wherein the flow control unit (43a, 143a) is used. The valve lift control pistons (42, 142) and the valve seating control pistons (43, 143) change the clearance area between the pistons of the hydraulic actuators according to the axial positions of the hydraulic actuators. The flow rate controller (42a, 43a, 142a, 143a) controls the flow rate of hydraulic pressure supplied to the hydraulic piston (22) and the flow rate of hydraulic pressure discharged from the hydraulic piston. Or an electronically controlled valve drive device for an internal combustion engine according to 3; The valve lift control piston (42, 142) and the valve seating control piston (43, 143) are accommodated in a piston accommodation hole (27a, 27b, 127a, 127b) provided in the end face of the piston of the hydraulic actuator. And a spring (46, 47, 146, 147) which is contracted between the bottom end of the piston receiving hole and the base end of the piston, and protrudes from the end face of the piston. An electronically controlled valve drive device for an internal combustion engine according to claim 2 . One end of the valve lift control piston (42) opens at the tip of the flow rate control unit (42a), and the other end of the valve lift control piston (42) enters the piston accommodation hole (27a) of the piston (27) of the hydraulic actuator (25). Open piston oil passages (42b, 42c) are provided, and one end of the piston of the hydraulic actuator opens to the end face of the piston on the valve lift control piston side, and the other end opens to the piston accommodation hole. 6. The internal combustion engine according to claim 3 , wherein a piston oil passage (27 c) communicating with the piston oil passage of the valve lift control piston is provided according to an axial position of the valve lift control piston. An electronically controlled valve drive for an engine. One end of the valve seating control piston (43) opens at the tip of the flow rate control section (43a) and the other end of the valve seating control piston (43) is in the piston accommodation hole (27b) of the piston (27) of the hydraulic actuator (25). Piston oil passages (43b, 43c) are provided, and one end of the piston of the hydraulic actuator opens to the end surface of the piston on the valve seating control piston side, and the other end opens to the piston accommodation hole. The internal combustion engine according to claim 3 or 5 , wherein a piston oil passage (27d) communicating with the piston oil passage of the valve seating control piston is provided according to an axial position of the valve seating control piston. An electronically controlled valve drive for an engine. The flow rate control part (42a) of the valve lift control piston (42) and the flow rate control part (43a) of the valve seating control piston (43) have a concave taper shape that is recessed inwardly, and the distal end from the base end part. 4. The electronically controlled valve drive device for an internal combustion engine according to claim 3 , wherein the valve is formed so as to be reduced in diameter toward the portion.

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